Methods of forming capacitors

ABSTRACT

Some embodiments include methods of forming capacitors. A metal oxide mixture may be formed over a first capacitor electrode. The metal oxide mixture may have a continuous concentration gradient of a second component relative to a first component. The continuous concentration gradient may correspond to a decreasing concentration of the second component as a distance from the first capacitor electrode increases. The first component may be selected from the group consisting of zirconium oxide, hafnium oxide and mixtures thereof; and the second component may be selected from the group consisting of niobium oxide, titanium oxide, strontium oxide and mixtures thereof. A second capacitor electrode may be formed over the first capacitor electrode. Some embodiments include capacitors that contain at least one metal oxide mixture having a continuous concentration gradient of the above-described second component relative to the above-described first component.

RELATED PATENT DATA

This patent resulted from a divisional of U.S. patent application Ser.No. 12/476,948, which was filed Jun. 2, 2009, which is now U.S. Pat. No.8,107,218, and which is hereby incorporated herein by reference.

TECHNICAL FIELD

Capacitors, and methods of forming capacitors.

BACKGROUND

Capacitors have many applications in integrated circuitry. For instance,dynamic random access memory (DRAM) unit cells may comprise a capacitorin combination with a transistor. Charge stored on the capacitors of theDRAM unit cells may correspond to memory bits.

A continuing goal of integrated circuit fabrication is to decrease thearea consumed by individual circuit components, and to thereby increasethe density of components that may be provided over a single chip (inother words, to increase the scale of integration). Thus, there is acontinuing goal to miniaturize the various components utilized inintegrated circuitry.

A problem that may occur during the miniaturization of capacitors isthat smaller capacitors may have correspondingly less capacitance thanlarger capacitors. The amount of charge that may be stored on individualcapacitors may be proportional to capacitance, and there may be aminimum capacitance per cell that is required for reliable memoryoperation. Accordingly, it is often not practical to simply scale-downthe size of existing capacitors to achieve capacitors suitable forfuture generations of integrated circuitry. Rather, the miniaturizedcapacitors will not meet desired performance parameters unless newmaterials are developed which improve capacitance within theminiaturized capacitors.

One method of increasing capacitance is to decrease the thickness ofdielectrics utilized in the capacitors. However, current leakage becomesproblematic with decreasing dielectric thickness.

It would be desirable to develop improved integrated circuit capacitorshaving desired capacitance, and not having problematic leakage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic cross-sectional side view of a semiconductorconstruction showing a pair of DRAM unit cells.

FIG. 2 is a diagrammatic cross-sectional side view of an exampleembodiment capacitor.

FIG. 3 is a diagrammatic cross-sectional side view of another exampleembodiment capacitor.

FIG. 4 is a diagrammatic cross-sectional side view of another exampleembodiment capacitor.

FIGS. 5-7 are diagrammatic cross-sectional side views of a constructionshown at various process stages of an example embodiment method offorming a capacitor.

FIGS. 8 and 9 are diagrammatic cross-sectional side views of aconstruction shown at various process stages of another exampleembodiment method of forming a capacitor.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

FIG. 1 shows a portion of a construction 10 comprising a pair of DRAMunit cells 6 and 8 supported by a semiconductor substrate 12.

Substrate 12 may comprise, consist essentially of, or consist of, forexample, monocrystalline silicon lightly-doped with background p-typedopant. The terms “semiconductive substrate” and “semiconductorsubstrate” mean any construction comprising semiconductive material,including, but not limited to, bulk semiconductive materials such as asemiconductive wafer (either alone or in assemblies comprising othermaterials thereon), and semiconductive material layers (either alone orin assemblies comprising other materials). The term “substrate” meansany supporting structure, including, but not limited to, thesemiconductive substrates described above.

The DRAM unit cells comprise capacitors in combination with transistors.Specifically, unit cell 6 comprises a capacitor 14 in combination with atransistor 16, and unit cell 8 comprises a capacitor 18 in combinationwith a transistor 20.

Transistors 16 and 20 comprise gates 17 and 21, respectively. The gatesinclude stacks containing gate dielectric material 24, electricallyconductive material 26, and an electrically insulative capping material28. The materials 24, 26 and 28 may comprise conventional materials. Forinstance, gate dielectric material 24 may comprise silicon dioxide;conductive material 26 may comprise one or more of various metals,metal-containing compounds, and conductively-doped semiconductormaterials; and capping material 28 may comprise one or more of silicondioxide, silicon nitride and silicon oxynitride. In some embodiments,the gates may be portions of wordlines that extend in and out of thepage relative to the cross-sectional view of FIG. 1.

Sidewall spacers 22 are along the sidewalls of gates 17 and 21. Thesidewall spacers may comprise conventional materials; and may, forexample, comprise one or more of silicon dioxide, silicon nitride andsilicon oxynitride.

The transistor 16 comprises a pair of source/drain regions 30 and 32 onopposing sides of gate 17; and similarly the transistor 20 comprisessource/drain regions 32 and 34 on opposing sides of gate 21. In theshown embodiment, source/drain region 32 is shared by the adjacenttransistors 16 and 20. The source/drain regions may correspond toconductively-doped diffusion regions extending into semiconductormaterial of substrate 12.

In the shown embodiment, an electrically conductive pedestal 36 isprovided over source/drain region 30 and in electrical connection tosource/drain region 30; and similarly an electrically conductivepedestal 37 is provided over source/drain region 34 and in electricalconnection with source/drain region 34. The pedestals 36 and 37 maycomprise any suitable electrically conductive compositions orcombinations of electrically conductive compositions. For instance, thepedestals 36 and 37 may comprise one or more of various metals,metal-containing compounds, and conductively-doped semiconductormaterials.

Capacitor 14 comprises a storage node electrode 38 in electricalconnection with pedestal 36. The storage node electrode is shown tohomogeneously comprise a single material 40. In other embodiments (notshown), the storage node electrode may comprise multiple differentmaterials. The shown material 40 may comprise any suitable electricallyconductive composition or combination of compositions; and may, forexample, comprise one or more of various metals, metal-containingcompounds, and/or conductively-doped semiconductor materials. In someembodiments, material 40 may comprise, consist essentially of, orconsist of titanium nitride.

Capacitor 14 also comprises a plate electrode 42. The plate electrode isshown to homogeneously comprise a single material 44. In otherembodiments (not shown), the plate electrode may comprise multipledifferent materials. The shown material 44 may comprise any suitableelectrically conductive composition or combination of compositions; andmay, for example, comprise one or more of various metals,metal-containing compounds, and/or conductively-doped semiconductormaterials. In some embodiments, material 44 may comprise, consistessentially of, or consist of titanium nitride.

The storage node electrode 38 and plate electrode 42 may be genericallyreferred to as being capacitor electrodes.

Capacitor 14 comprises capacitor dielectric 46 between the capacitorelectrodes 38 and 42. The capacitor dielectric 46 is shown to comprisetwo different materials 48 and 50. In other embodiments, the capacitordielectric may comprise only a single material, or may comprise morethan two materials.

In some embodiments, the capacitor dielectric will include a metal oxidemixture that has a continuous concentration gradient of one componentrelative to another. Specifically, a dielectric composition with a highdielectric constant (for instance, a dielectric composition selectedfrom the group consisting of niobium oxide, titanium oxide, strontiumoxide and mixtures thereof) is mixed with a dielectric compositionhaving a lower dielectric constant (for instance, a dielectriccomposition selected from the group consisting of zirconium oxide,hafnium oxide and mixtures thereof) to form a continuous concentrationgradient of the high dielectric constant composition relative to the lowdielectric constant composition.

The high dielectric constant composition will have a desired highdielectric constant, but will also tend to have undesired small bandgapsand corresponding high leakage characteristics. In contrast, the lowdielectric constant composition will tend to have desired wide bandgapsand corresponding low leakage characteristics; but will also tend tohave an undesired low dielectric constant. By combining the highdielectric constant composition with the low dielectric constantcomposition in a metal oxide mixture, the desired properties of each maybe obtained across a thickness of the metal oxide mixture.

It may be advantageous for the highest concentration of the highdielectric constant composition to be near a capacitor electrode, and tothen have the concentration of the high dielectric constant compositionfall off as a distance from the capacitor electrode increases. Inembodiments in which capacitor dielectric 46 comprises two or moredifferent materials, the metal oxide mixture may be utilized as one ofthe materials of the capacitor dielectric, or as multiple materials ofthe capacitor dielectric. For instance, either or both of the dielectricmaterials 48 and 50 of capacitor dielectric 46 may be a metal oxidemixture.

In the shown embodiment, dielectric material 48 is adjacent storage nodeelectrode 38. If material 48 is a mixture of a high dielectric constantcomposition and a low dielectric constant composition, the concentrationof the high dielectric constant composition may increase along acontinuous concentration gradient extending from an upper surface ofmaterial 48 to a lower surface of material 48, as indicated by an arrow49 provided adjacent material 48. Similarly, if the dielectric material50 is a mixture of a high dielectric constant composition and a lowdielectric constant composition, the concentration of the highdielectric constant composition may increase along a continuousconcentration gradient extending from a lower surface of material 50 toan upper surface of material 50, as indicated by a dashed-line arrow 51provided adjacent material 50.

Capacitor 18 is similar to the above-discussed capacitor 14, andcomprises a storage node electrode 52 in electrical connection withpedestal 37. Storage node electrode 52 may comprise any of the materialsdiscussed above regarding storage node electrode 38, and is shown tohomogeneously comprise the single material 40.

Capacitor 18 comprises the plate electrode 42 that was discussed above;and also comprises the capacitor dielectric 46 that was discussed above.

The diagram of FIG. 1 shows that the capacitor plate electrode may bedistinguished from storage node electrodes of DRAM in that the capacitorplate electrode (specifically, electrode 42 of FIG. 1) is shared acrossnumerous capacitors, while the storage node electrodes (specifically,electrodes 38 and 52 of FIG. 1) are unique to individual capacitors.

Each of the capacitors is electrically connected to one of thesource/drain regions of a transistor (for instance, in the shownembodiment the source/drain regions 30 and 34 of transistors 16 and 20,respectively, are electrically connected to capacitors 14 and 18,respectively). The remaining source/drain region of the transistor maybe electrically connected to a bitline. In FIG. 1, the sharedsource/drain region 32 of transistors 16 and 20 is diagrammaticallyillustrated as being electrically connected to a bitline 54. Inoperation, bitlines and wordlines may correspond to rows and columns ofa memory array, and individual capacitors may be uniquely addressed atcrosspoints of the rows and columns.

The construction 10 of FIG. 1 is a generic representation of a portionof a DRAM array, and numerous aspects of such construction may be variedin specific embodiments (not shown). In the shown embodiment, a block ofelectrically insulative material 56 is provided between capacitors 18and 14 to electrically isolate the storage node electrodes of thecapacitors from one another. The capacitors are shown having a simplegeometric configuration of stacked plates, and the interveninginsulative material 56 is shown having a simple geometric configurationof a contiguous block. In other embodiments, the capacitors may havemore complex geometric configurations (for instance, the capacitors maybe container-type capacitors or pedestal-type capacitors), and likewisematerial 56 may be formed in a more complex geometric configuration.Also, pedestals 36 and 37 may be omitted in some embodiments, so thatstorage nodes 38 and 52 are formed in direct physical contact withsource/drain regions 30 and 34.

An additional modification that may be made relative to the construction10 of FIG. 1 is that the capacitor dielectric 46 may be tailored forparticular embodiments. FIGS. 2-9 illustrate particular configurationsof capacitor dielectric 46 relative to example capacitors and methods offorming capacitors.

Referring to FIG. 2, a capacitor 60 is shown to comprise a pair ofcapacitor electrodes 62 and 64, and dielectric material 46 between thecapacitor electrodes. One of the capacitor electrodes 62 and 64 maycorrespond to a storage node electrode analogous to the electrode 38 ofFIG. 1, and the other of the electrodes 62 and 64 may correspond to acapacitor plate electrode analogous to the electrode 42 of FIG. 1.Either of the electrodes 62 and 64 may be the storage node electrode,and accordingly either of the electrodes 62 and 64 may be the capacitorplate electrode. The electrodes 62 and 64 may be referred to as a firstcapacitor electrode and a second capacitor electrode, respectively.

The dielectric material 46 of capacitor 60 contains materials 66, 68,70, 72 and 74. The materials 66, 70 and 74 are shown to be thin layers,while the materials 68 and 72 are thicker layers. Dielectric material 46may have any suitable overall thickness, and in some embodiments mayhave a thickness of from about 80A to about 150A.

The material 68 may be a metal oxide mixture comprising a continuousconcentration gradient of one component relative to another. In someembodiments, the material 68 may be a mixture of a metal oxide having ahigh dielectric constant with a metal oxide having a low dielectricconstant, with a concentration of the high dielectric constant metaloxide increasing along a continuous concentration gradient extendingfrom an upper surface of material 68 to a lower surface of material 68,as indicated by an arrow 69 provided adjacent material 68. The metaloxide with the high dielectric constant may be selected from the groupconsisting of niobium oxide (i.e., NbO_(a), where “a” is greater thanzero), titanium oxide (i.e., TiO_(b), where “b” is greater than zero),strontium oxide (i.e., SrO_(c), where “c” is greater than zero) andmixtures thereof. The metal oxide with the low dielectric constant maybe selected from the group consisting of zirconium oxide (i.e., ZrO_(d),where “d” is greater than zero), hafnium oxide (i.e., HfO_(e), where “e”is greater than zero) and mixtures thereof. Accordingly, in someembodiments material 68 may comprise, consist essentially of, or consistof a mixture of a first component selected from the group consisting ofzirconium oxide, hafnium oxide and mixtures thereof; with a secondcomponent selected from the group consisting of niobium oxide, titaniumoxide, strontium oxide and mixtures thereof.

The continuous concentration gradient within material 68 may bedescribed as follows. The upper surface of material 68 may be consideredto comprise a first atomic percentage of the high dielectric constantmetal oxide (which in some embodiments may be 0 atomic percent, and inother embodiments may be greater than 0 atomic percent). The lowersurface of material 68 may be considered to comprise a second atomicpercentage of the high dielectric constant metal oxide. The secondatomic percentage is greater than the first atomic percentage, and theatomic percentage of the high dielectric constant metal oxide increasescontinuously throughout a thickness of material 68.

In some embodiments, the high dielectric constant metal oxide consistsof niobium oxide, and the low dielectric constant metal oxide consistsof one or both of zirconium oxide and hafnium oxide. In suchembodiments, the first atomic percentage of the niobium oxide may beless than or equal to 50 percent, and the second atomic percentage ofthe niobium oxide may be less than or equal to 100 percent. In the shownembodiment, the continuous concentration gradient of the niobium oxidewithin material 68 (illustrated by arrow 69) results in an increasingconcentration of niobium oxide as a distance from the capacitorelectrode 62 decreases.

The utilization of a continuous concentration gradient of the highdielectric constant metal oxide within material 68 may enable more ofthe high dielectric constant metal oxide to be effectively incorporatedinto material 68 than could be accomplished utilizing a non-continuousconcentration gradient (such as a step gradient).

Material 68 may be formed to any suitable thickness. In some exampleembodiments, material 68 may have a thickness of from about 10 Å toabout 70 Å; and in some example embodiments may have a thickness ofabout 30 Å.

Material 72 may comprise a dielectric material that is provided inaddition to material 68 in order to tailor dielectric properties ofmaterial 46 to achieve specific desired parameters of the material 46.In some embodiments, material 72 may comprise, consist essentially of,or consist of one or both of hafnium oxide and zirconium oxide. In someembodiments, materials 68 and 72 may be referred to as first and seconddielectric materials, respectively.

In some embodiments, materials 66, 70 and 74 may comprise, consistessentially of, or consist of aluminum oxide and may be utilized asbarriers to impede migration of niobium, titanium and/or strontium frommaterial 68. In such embodiments, materials 66, 70 and 74 may be formedto be less than 10 Å thick, less than 5 Å thick, or even less than 4 Åthick. One or more of the materials 66, 70 and 74 may be omitted in someembodiments.

Referring to FIG. 3, a capacitor 80 is shown to comprise the pair ofcapacitor electrodes 62 and 64, discussed above with reference to FIG.2, and to comprise dielectric material 46 between the capacitorelectrodes. The capacitor dielectric 46 of capacitor 80 containsmaterials 82, 84, 86 and 88. An overall thickness of the material 46 ofcapacitor 80 may be from about 80 Å to about 150 Å.

Material 82 may comprise, consist essentially of, or consist of amixture of aluminum and oxygen together with one or both of hafnium andzirconium; and specifically may comprise, consist essentially of, orconsist of a mixture of aluminum oxide and one or both of hafnium oxideand zirconium oxide. Material 82 may be amorphous, rather thancrystalline. Although material 82 is shown directly against bottomelectrode 62, in other embodiments there may be an intervening thinlayer of aluminum oxide provided between material 82 and the bottomelectrode.

Material 84 may comprise, consist essentially of, or consist of aluminumoxide, and may have a thickness of less than 10Å, less than 5Å, or lessthan or equal to 4Å in some embodiments. Material 84 may be omitted insome embodiments.

Material 86 may comprise, consist essentially of, or consist of one orboth of zirconium oxide and hafnium oxide, and may be crystalline.

Material 88 may be a metal oxide mixture comprising a continuousconcentration gradient of one component relative to another, and may beidentical to the material 68 discussed above with reference to FIG. 2.An arrow 89 is provided adjacent material 88 to illustrate aconcentration gradient of a high dielectric constant component withinmaterial 88. Material 88 may be crystalline, amorphous, or a combinationof crystalline and amorphous.

Although either of capacitor electrodes 62 and 64 may be the storagenode electrode of the capacitor, in some embodiments it may beadvantageous for electrode 62 to be the storage node electrode in theconfiguration shown in FIG. 3.

The capacitors of FIGS. 2 and 3 are asymmetric relative to thedistribution of capacitor dielectric between the capacitor electrodes.FIG. 4 illustrates an alternative capacitor 90 that has a symmetricdistribution of capacitor dielectric between the capacitor electrodes 62and 64.

The capacitor dielectric 46 of capacitor 90 contains materials 92, 94,96, 98 and 100.

Materials 94 and 98 may be metal oxide mixtures comprising continuousconcentration gradients of one component relative to another, and may beidentical to the material 68 discussed above with reference to FIG. 2.In some embodiments, the materials 94 and 98 may be compositionallyidentical to one another, and may be mirror images of one another. Anarrow 95 is provided adjacent material 94 to illustrate a concentrationgradient of a high dielectric constant component within material 94, andan arrow 99 is provided adjacent material 98 to illustrate aconcentration gradient of a high dielectric constant component withinmaterial 98. Arrow 95 shows the concentration of the high dielectricconstant component in material 94 increasing in a direction toward theillustrated bottom electrode 62. In contrast, arrow 99 shows theconcentration of the high dielectric constant component in material 98increasing in a direction toward the illustrated top electrode 64.

In some embodiments, the components of the mixed metal oxide of material94 may be referred to as a first component and a second component; withthe first component being one or more low dielectric constantcompositions (such as one or both of hafnium oxide and zirconium oxide),and the second component being one or more high dielectric constantcompositions (such as one or more of niobium oxide, titanium oxide andstrontium oxide). In such embodiments, the components of the mixed metaloxide of material 98 may be referred to as a third component and afourth component; with the third component being one or more lowdielectric constant compositions, and the fourth component being one ormore high dielectric constant compositions. The first and thirdcomponents may be the same as one another in some embodiments, or may bedifferent from one another in other embodiments. Similarly, the secondand fourth components may be the same as one another in someembodiments, or may be different from one another in other embodiments.

Materials 92, 96 and 100 may comprise, consist essentially of, orconsist of aluminum oxide, and may have thickness of less than 10 Å,less than 5 Å, or less than or equal to 4Å in some embodiments. One ormore of materials 92, 96 and 100 may be omitted in some embodiments.

The capacitors of FIGS. 1-4 may be formed with any suitable methodology.An example method for forming the capacitor 60 of FIG. 2 is describedwith reference to FIGS. 5-7.

Referring to FIG. 5, construction 60 is shown at a processing stageafter material 66 has been formed across the illustrated bottomelectrode 62. The bottom electrode may be formed over a supportingsubstrate (not shown) utilizing one or more of physical vapor deposition(PVD), atomic layer deposition (ALD) and chemical vapor deposition(CVD).

Material 66 may be deposited over electrode 62 utilizing one or both ofALD and CVD. For instance, if material 66 consists of aluminum oxide,such may be formed by ALD utilizing sequential pulses of analuminum-containing precursor and an oxygen-containing precursor. In theshown embodiment, material 66 is directly against (i.e., touching)electrode 62.

Referring to FIG. 6, the metal oxide mixture of material 68 is formedover material 66. In the shown embodiment, material 68 is directlyagainst material 66.

The metal oxide mixture of material 68 has two components, as discussedabove with reference to FIG. 2. One of the components may be referred toas a first component, and may comprise one or both of zirconium oxideand hafnium oxide; and the other of the components may be referred to asa second component, and may comprise one or more of niobium oxide,titanium oxide and strontium oxide. The concentration of the secondcomponent increases continuously in progressing from an upper surface ofmaterial 68 to a lower surface of the material, as indicated by thearrow 69 provided adjacent material 68.

The metal oxide mixture of material 68 may be formed utilizing one orboth of ALD and CVD. For instance, if CVD is utilized a mixture ofprecursors may be provided within a reaction chamber. One of theprecursors may lead to formation of the first component of the metaloxide mixture of material 68, and a second of the precursors may lead toformation of the second component of the metal oxide mixture of material68. The relative amount of the second component of the metal oxidemixture to the first component of the metal oxide mixture may becontinuously varied by continuously altering the ratio of the secondprecursor to the first precursor within the deposition chamber.

If ALD is utilized to form material 68, the material will be formed as aplurality of separate layers which are then diffused into one anotherwith a subsequent anneal. Thus, material 68 may be initially formed as astack of thin layers deposited with ALD. Some of layers may comprise thefirst component of the metal oxide mixture material 68, while others ofthe layers comprise the second component of such metal oxide mixture.The relative amount of the second component to the first component maybe varied within the stack by altering the number of layerscorresponding to the first component relative to the number of layerscorresponding to the second component. Prior to the anneal of thedeposited layers, the bottom of material 68 will comprise a higherpercentage of layers containing a second component of the metal oxidemixture than will the top of material 68, and the percentage of layerscontaining a second component of the metal oxide mixture will varythroughout the stack. After annealing of the stack and the accompanyingdiffusion of the layers into one another, material 68 will have acontinuously varying gradient corresponding to the concentration of thesecond component of the metal oxide mixture relative to the firstcomponent of the metal oxide mixture.

In some embodiments, the ALD may comprise sequential pulses ofmetal-containing precursor and oxygen-containing precursor to form astack of metal oxide layers. In other embodiments, the ALD may utilizesequential pulses of a first metal-containing precursor, a secondmetal-containing precursor, and an oxygen-containing precursor (aso-called “MMO” pulse) to form at least some of the layers within thestack to contain two or more metals in combination with oxygen. If theALD utilizes MMO pulses, individual layers formed by the ALD may containboth the second component of the metal oxide mixture and the firstcomponent of the metal oxide mixture. In such embodiments, theconcentration of the second component of the metal oxide mixture may bevaried by changing a relative amount of the second component of themetal oxide mixture to the first component of the metal oxide mixturewithin individual layers.

Referring to FIG. 7, the materials 70, 72 and 74 are fowled overmaterial 68; and the top electrode 64 is formed over material 74. Thevarious materials 70, 72, 74 may be formed utilizing any suitableprocessing, including, for example, one or both of ALD and CVD; and thetop electrode 64 may be formed utilizing one or more of ALD, CVD andPVD.

An example method for forming the capacitor 90 of FIG. 4 is describedwith reference to FIGS. 8 and 9.

Referring to FIG. 8, construction 90 is shown at a processing stageafter material 92 has been formed across the illustrated bottomelectrode 62, and after material 94 has been formed over material 92.

The bottom electrode 62 may be formed over a supporting substrate (notshown) utilizing one or more of physical vapor deposition (PVD), atomiclayer deposition (ALD) and chemical vapor deposition (CVD).

Material 92 may be deposited over electrode 62 utilizing one or both ofALD and CVD. For instance, if material 92 consists of aluminum oxide,such may be formed by ALD utilizing sequential pulses of analuminum-containing precursor and an oxygen-containing precursor.

The metal oxide mixture of material 94 may be formed utilizingprocessing analogous to that discussed above with reference to FIG. 6relative to formation of material 68.

Referring to FIG. 9, the materials 96, 98 and 100 are formed overmaterial 94; and the electrode 64 is formed over material 100. Material98 may be formed utilizing processing analogous to that discussed abovewith reference to FIG. 6 relative to formation of material 68. Thematerials 96 and 100 may be formed utilizing any suitable processing,including, for example, one or both of ALD and CVD; and the topelectrode 64 may be formed utilizing one or more of ALD, CVD and PVD.

The processing of FIGS. 5-9 forms the capacitor 60 that had beendescribed with reference to FIG. 2, and the capacitor 90 that had beendescribed with reference to FIG. 4. Processing analogous to that ofFIGS. 5-9 may be used to form the capacitor 80 of FIG. 3. Specifically,materials 82, 84 and 86 of FIG. 3 may be formed with any suitableprocessing, such as, for example, one or both of ALD and CVD; andmaterial 88 of FIG. 3 may be formed with processing analogous to thatdiscussed above with reference to FIG. 6 relative to formation ofmaterial 68.

In compliance with the statute, the subject matter disclosed herein hasbeen described in language more or less specific as to structural andmethodical features. It is to be understood, however, that the claimsare not limited to the specific features shown and described, since themeans herein disclosed comprise example embodiments. The claims are thusto be afforded full scope as literally worded, and to be appropriatelyinterpreted in accordance with the doctrine of equivalents.

We claim:
 1. A method of forming a capacitor, comprising: depositingdifferent metal oxides over a lower capacitor electrode andincorporating the different metal oxides into a metal oxide mixture overthe lower capacitor electrode; the different metal oxides beingdeposited in a ratio relative to one another, with such ratio formingthe metal oxide mixture to comprise a continuous concentration gradientof a second component relative to a first component; the continuousconcentration gradient comprising a decreasing concentration of thesecond component as a distance from the lower capacitor electrodeincreases; the first component being selected from the group consistingof zirconium oxide, hafnium oxide and mixtures thereof; the secondcomponent being selected from the group consisting of niobium oxide,titanium oxide, strontium oxide and mixtures thereof; and forming anupper capacitor electrode over the metal oxide mixture.
 2. The method ofclaim 1 wherein the depositing of the different metal oxides utilizesatomic layer deposition.
 3. The method of claim 1 wherein the depositingof the different metal oxides utilizes chemical vapor deposition.
 4. Themethod of claim 1 further comprising: forming a layer consisting ofaluminum oxide over and directly against the lower capacitor electrode;and forming the metal oxide mixture over and directly against the layerconsisting of aluminum oxide.
 5. The method of claim 1 wherein thesecond component is niobium oxide.
 6. A method of forming a capacitor,comprising: forming a capacitor dielectric material over a lowercapacitor electrode; depositing different metal oxides over thecapacitor dielectric material and incorporating the different metaloxides into a metal oxide mixture over the capacitor dielectricmaterial; the different metal oxides being deposited in a ratio relativeto one another, with such ratio forming the metal oxide mixture tocomprise a continuous concentration gradient of a second componentrelative to a first component; the first component being selected fromthe group consisting of zirconium oxide, hafnium oxide and mixturesthereof; the second component being selected from the group consistingof niobium oxide, titanium oxide, strontium oxide and mixtures thereof;and forming an upper capacitor electrode over the metal oxide mixture;the continuous concentration gradient comprising an increasingconcentration of the second component as a distance from the uppercapacitor electrode decreases.
 7. The method of claim 6 wherein thecapacitor dielectric material is a first capacitor dielectric material,and wherein the forming of the first capacitor dielectric materialcomprises depositing a mixture of aluminum, oxygen and one or both ofzirconium and hafnium; and further comprising: forming a secondcapacitor dielectric material over the first capacitor dielectricmaterial; wherein the forming of the second capacitor dielectricmaterial comprises depositing one or both of hafnium oxide and zirconiumoxide; and forming the metal oxide mixture over and directly against thesecond capacitor dielectric material.
 8. The method of claim 7 whereinthe second component is niobium oxide.
 9. The method of claim 7 furthercomprising: depositing aluminum oxide over and directly against thefirst capacitor dielectric material; and forming the second capacitordielectric material over and directly against the aluminum oxide thathad been deposited over and directly against the first capacitordielectric material.
 10. The method of claim 9 wherein the secondcomponent is niobium oxide.